1. Technical Field of the Invention
This invention relates to a method for the preparation of predominantly linear polyethylenepolyamines by reacting ethylenediamine with monoethanolamine in the presence of a catalyst consisting essentially of phosphate supported on a heterogeneous titania/zirconia support.
The catalysts that are used in accordance with the present invention are composed of phosphorus, titania and zirconia. They are prepared by mixing solutions of a tetravalent compound of titanium with a tetravalent compound of zirconium, treating the solution to simultaneously coprecipitate titania and zirconia to form a heterogenous titania/zirconia support, recovering the coprecipitate, treating it with a phosphorus compound to bond from about 0.5 to 6 wt. % of phosphorus to the coprecipitate and then stabilizing the resultant catalyst by calcining it at about 200.degree. to about 800.degree. C.
2. Prior Art
Heretofore, polyethylenepolyamine compounds such as diethylenetriamine, triethylenetetramine and the higher homologs have been produced by the reaction of an alkyl halide such as ethylene dichloride with an amine such as ammonia or ethylenediamine at elevated temperatures and pressures. Normally, relatively high yields of predominantly noncyclic polyethylenepolyamine compounds are obtained from this process with varying yields of heterocyclic amines. The large amounts of energy required to produce the reactants as well as the difficult separation procedures required to recover the more valuable linear polyethylenepolyamines diminish the utility of the ethylene dichloride process. The hydrohalide salts of ammonia and the polyethylenepolyamine products must also undergo difficult and time consuming caustic neutralization to yield the free polyethylenepolyamines.
Investigators have found that more linear products can also be obtained in a catalytic conversion. Thus, Ford et al. U.S. Pat. No. 4,316,840 discloses the preparation of polyalkylenepolyamines from ethylenediamine utilizing a metal nitrate or sulfate as a catalyst. U.S. Pat. No. 4,314,083 discloses the reaction of ethylenediamine with monoethanolamine to prepare noncyclic polyalkylenepolyamines using, as a catalyst, a salt of a nitrogen or sulfur-containing compound.
Ford et al. U.S. Pat. No. 4,362,886 discloses a process for preparing predominantly non-cyclic polyalkylenepolyamine compounds from feedstocks such as ethylenediamine and ethanolamine using a compound of antimony, bismuth or arsenic as a catalyst. In Ford et al. U.S. Pat. No. 4,399,308, a Lewis acid halide is used to catalyze the reaction. In European patent application No. 0073520, Ford et al. disclose the use of a phosphorous-containing substance such as boron phosphate or a salt of a sulfur-containing substance such as beryllium sulfate, boron sulfate or ammonium sulfate as the catalyst.
Brennan et al. U.S. Pat. No. 4,036,881 discloses the use of phosphorous-containing catalysts to catalyze the reaction of ethylenediamine with monoethanolamine.
In Vanderpool U.S. Pat. No. 4,524,152, entitled "Catalytic Preparation of Linear Polyethylenepolyamines with Supported Catalysts", a process for the preparation of linear polyethylenepolyamines is disclosed wherein monoethanolamine is reacted with ethylenediamine in the presence of zirconium silicate to which phosphorous has been thermally bonded. Vanderpool U.S. Pat. No. 4,588,842 entitled "Catalytic Preparation of Polyethylenepolyamines" discloses the use of zirconia having phosphorous thermally bonded thereto as a catalyst for promoting the reaction of ethylenediamine with monoethanolamine to provide essentially linear polyethylenepolyamine reaction products.
In addition, Vanderpool U.S. Pat. No. 4,540,822 issued Sept. 10, 1985 discloses a process for making essentially linear polyethylenepolyamines by reacting monoethanolamine with ethylenediamine in the presence of a catalyst composed of a minor amount of phosphorus thermally, chemically bonded to a group IVb metal oxide support wherein the catalyst is periodically regenerated. In Vanderpool et al. U.S. Pat. No. 4,609,761 which issued Sept. 2, 1986, a catalyst for this reaction is disclosed wherein a trialkyl phosphate or a trialkyl phosphite is initially deposited on titania as a source of phosphorus, and in Renken U.S. Pat. No. 4,612,397 which issued Sept. 16, 1986, a diammonium hydrogen phosphate is used as a source for the phosphorus in preparing the catalyst.
French Pat. No. 1,317,359 dated Feb. 8, 1963, discloses the preparation of granulated zirconium phosphate and its use as an ion-exchange resin. Winkler et al. in a 1966 publication [Deutsche Akad. Wiss., Berlin, Germany, Z. Anorg. Allgen. Chem. 346 (1-2), 92-112 (1966)] disclose compounds of the general formula HX.sup.v P.sub.2 O.sub.3 wherein X represents arsenic, antimony and mixtures thereof. Also disclosed are compounds of the general formula H.sub.2 X.sup.iv P.sub.2 O.sub.3, wherein X represents silicon, germanium, tin, lead, titanium and zirconium. It is shown that the group IV phosphates have cation exchange properties.